Well, you can check your answer by just using trig like you did earlier.
[tex]F_1 = F_{2}*cos(30) = 1500*sqrt{3}[/tex]

You fell into the unfortunate trap of notation. The definition of a moment is that M = B x r, which shows us that the moment is the cross product of the vector and the scalar where the vector is applied. You should go back and nail down the concept of moments, then try the problem out again.